Turf aerators are well known in the art, and they are of the type which includes a mobile unit movable over the ground and which articularly supports and powers an assembly of a crank mechanism and turf penetrating tines. The arrangements are such that the cranks are powered to cyclically move the tines in both the vertical and horizontal directions so that the tines will penetrate the ground while the unit is moving forward, and the tines will then also remain in the ground and finally be extracted from the ground, again while the unit is still moving forward.
The concern in turf aerating is to form the aerating holes in a constricted but vertical pattern so that the holes are only of the cross section dimension desired, that is, the holes are not formed with a tine which tilts or moves horizontally while the tines are in the ground. The present invention accomplishes this by having a parallelogram arrangement whereby the tines remain vertically oriented throughout their crank-type movement.
Still further, the aforementioned is accomplished and the aerator is arranged to have the cranks and tines in two side-by-side sets so that they can alternately penetrate the ground and perform the desired walking action during the forward movement of the entire machine. In that arrangement, each set includes the crank and the crank arms and the tine assembly, and there two complete sets, in side-by-side arrangement, both of which are actuated off a common shaft and both of which have two crank arms disposed in the fore-and-aft plane of the turf aerating direction of movement of the machine.
In accomplishing the aforementioned, the-aerator is arranged to be stable in the direction of the fore-and-aft aerating movement and in the direction lateral thereto.
Also, the apparatus is arranged to selectively position the tines in an elevated service position.